Synthesis of Information Related to Highway Practices. Topic 56-20. Pavement Design and Evaluation of Low Volume Roads with Heavy Loads

Low-volume road (LVR) networks function as the primary link to highway transportation systems as well as the connection of communities. The structural capacity of LVRs plays a vital role in providing competent, stable, and durable roads. While state DOTs and FHWA have invested significant resources in improving the structural design of high-volume pavements, the structural design of LVRs, particularly local access roads in rural areas, often goes overlooked. LVRs built following a template design or minimum local standards may be sufficient for passenger vehicles, but once LVRs are subjected to heavy traffic from agriculture, renewable and non-renewable energy development, or logging operations, the structural capacity of LVRs is compromised and severe damage occurs. The damage from heavy loads can be further exacerbated by seasonal impacts such as spring thaw. When designing pavements for LVRs, many LVR owners and managers follow the AASHTO design guide, which converts axle loads into equivalent single-axle loads (ESALs) by using load equivalency factors (LEFs). However, these design practices may not adequately account for heavy loads (i.e., overweight standard trucks and non-standard axle-configurations) nor were they developed to provide designs for all types of LVRs (i.e., paved, unpaved, and unimproved types). LVRs that experience a high percentage of heavy standard trucks and overweight non-standard traffic and commensurately high loads suffer rapid and premature road deterioration. Such failures are often attributed to overweight loads applied to a substandard road design. To address such failures, it is crucial to improve the structural design of LVRs carrying overweight loads (i.e., apply factors to ensure a more robust pavement structure). The objective of this synthesis is to document current state DOT practice for the structural design of LVRs (i.e., paved, unpaved, and unimproved types), particularly those exposed to heavy loads. The synthesis will also identify opportunities for future research to modify current evaluation methods and design standards to provide LVR networks that can effectively accommodate heavy loads and prevent premature structural failure.


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  • Status: Proposed
  • Funding: $55000
  • Contract Numbers:

    Project 20-05, Topic 56-20

  • Sponsor Organizations:

    National Cooperative Highway Research Program (NCHRP) Synthesis

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Harrigan, Edward

  • Start Date: 20240501
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01920384
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic 56-20
  • Files: TRB, RIP
  • Created Date: May 31 2024 8:08PM